This row counter uses magnetic induction for easy installation and accurate counting. Press the Counting/Pause key to stop counting. After 0-30 seconds, the LCD indication will automatically turn off and enter a standby state. Press the key again to turn on the indication and continue counting. The shockproof design ensures stable and reliable system operation, free from mechanical abrasion. Constructed from durable plastic for safe operation and a long lifespan. Powered by a common AA battery, free from an external power supply. The working temperature of the magnet should be within 70 degrees; too high a temperature will make the magnet lose its magnetism and render the induction invalid. Features a five-digit LCD display with ultra-low power consumption for a large and clear readout. Color: As Shown. Material: Plastic. Size: Hole Size: 2.5x1.4 Inch. Power Supply: 1.5V AA battery (not included). Usable Ambient Temperature: -5 to 40C. Magnetic Induction Range: Approximately 5-10 mm. Maximum Counting Speed: 20 times per second.